1. Field of the Invention
The present invention relates to an optically active transition metal-diamine complex useful as a catalyst for various asymmetric organic synthesis reactions, etc., or the like, and a process for producing an optically active alcohol with the same.
2. Description of the Related Art
Hitherto, many transition metal complexes have been used as catalysts for organic metal reactions. In particular, because novel metal complexes are highly active, stable and easy to handle although they are expensive, many synthesis reactions using novel metal complexes as a catalyst have been developed, inter alia, there is a remarkable development in asymmetric synthesis reactions using an asymmetric complex as a catalyst. There have been made a large number of reports on an improvement of the efficiency of organic synthesis reaction which was inefficient with conventional means.
Among these reactions, asymmetric reactions using an asymmetric complex having an optically active phosphine ligand as a catalyst have been very widely developed, and some of them have been industrialized. Also, for example, there are many complexes, wherein a transition metal such as ruthenium, rhodium and iridium is coordinated with an optically active nitrogen compound, having excellent performances as a catalyst for asymmetric synthesis reactions. In order to improve the performances of the catalysts, a great number of optically active nitrogen compounds having a special structure have been developed so far (Non-patent Document 1 and so on).
For example, Non-patent Documents 2 and 3 report complexes wherein ruthenium is coordinated with optically active N-p-toluenesulfonyl-1,2-diphenylethylenediamine as a ligand. However, any reaction using this ligand is conducted in an organic solvent, and there has not been reported any example wherein the reaction is conducted only in water. When productions of pharmaceutical intermediates or the like are attempted by methods described therein, the resultant intermediate is not easily separated from the intermediate and the catalyst by operation such as distillation since many of these intermediates are in a solid form.
As described above, the separation of a catalyst and a product is one of the unavoidable problem. In particular, in homogeneous catalyst reactions, the catalyst used therein is easily dissolved in the organic layer therein; therefore, in order to separate the catalyst and the product, a complicated method such as distillation, recrystallization and the like is necessary.
For example, Patent Document 1 discloses an asymmetric hydrogenation using a sulfonated-BINAP. However, the document does not disclose any method for recovering a catalyst dissolved in water or reuse thereof after the hydrogenation.
Non-patent Document 4 reports a transfer hydrogenation type reduction using a ligand wherein the phenyl group of benzenesulfonyl-1,2-diaminocyclohexane is sulfonated at the para-position. The reaction, however, is conducted in a solvent of isopropanol-water. It is, therefore, necessary that a product therein is separated by distillation.
One method for solving such a problem of separation of a product and a catalyst would be a method of using a water-soluble catalyst to conduct a reaction in a solvent system containing water. In this case, the resultant product is dissolved in the organic layer therein and the catalyst is dissolved in the water layer. It therefore appears that the catalyst can easily be separated only by extraction operation. Non-patent Document 5, for example, describes a process for producing 1,2-bis(4-N,N-dimethylaminophenyl)ethylenediamine as a water-soluble amines, which is a racemic form. However, Non-patent Document 5 does not describe any optically active substance of the diamine, and the document neither describes any example of production of an optically active transition metal-diamine complex using above diamine as a ligand nor the use of said optically active transition metal-diamine complex as a catalyst for asymmetric hydrogenation. Also, Non-patent Document 6 describes 1,2-bis(4-N,N-dimethylaminophenyl)ehylenediamine and dichloro(1,2-bis(4-N,N-dimethylaminophenyl)ehylenediamine) platinum (II) complex which are racemic forms, and anticancer effect by use of said platinum complex. However, Non-patent Document 6 neither describes any optically active substances of the diamine nor the platinum complex, and the document also does not describe the use of the platinum catalyst as a catalyst for asymmetric hydrogenation.    Patent Document 1: JP-A-H05-170780    Non-patent Document 1: Chem Rev., 92, 1051-1069 (1992)    Non-patent Document 2: J. Am. Chem. Soc., vol. 117, 7562-7563 (1995)    Non-patent Document 3: J. Am. Chem. Soc., vol. 118, 4916-4917 (1996)    Non-patent Document 4: Tetrahedron Lett., vol. 42, 4041-4043 (2001)    Non-patent Document 5: Tetrahedron Lett., vol. 42, 2365-2368 (2001)    Non-patent Document 6: J. Cancer Res. Clin. Oncol., 114, 347-358 (1998)